Abstract: Using Aspen Plus V14 process simulation software, simulate the refinery gas fractionation process and verify the accuracy of the simulation process. Conventional single column distillation, co current double effect distillation, and counter current double effect distillation models were established for the propylene distillation unit. After simulation comparison, counter current double effect distillation was determined to be the best solution, and the purity of the refined propylene product reached 99.76%. The condenser heat load and reboiler heat load were reduced by 52.7% and 53.4%, respectively, compared to single column distillation. Preliminary optimization of countercurrent double effect distillation was carried out using sensitivity analysis tools; On this basis, further optimization was carried out using orthogonal experiments, and the optimal parameters for countercurrent double effect distillation were obtained as follows: The top extraction rate of the low-pressure tower was 62 kmol/h, the feed tray position of the low-pressure tower was the 46th plate (from top to bottom), the feed tray position of the high-pressure tower was the 42nd plate (from top to bottom), and the reflux molar ratio of the high-pressure tower was 14.

Key words: double effect distillation, gas fractionation process, propylene distillation tower, simulation optimization, energy conservation